Currently if I press Ctrl+Tab again and again, repeatedly, when I hit the last tab, and press again, Firefox goes to the first tab. How can I disable this? (And also disable vice-versa.) I would like Firefox to stop on the last tab, like a tab-stop.

Note: I would like to keep the Ctrl+Tab shortcut for in-between tabs. Only the start/end should behave differently (by not cycling).